The objective of this proposed research is to clarify aspects of cellular dynamics of the isolated type 1 epithelial cell of lung. This will include isolation and purification of type 1 pneumocytes from dispersed heterogeneous lung cells with subsequent identification by means of type 1 cell characteristics. Light and electron microscopy, involving specific light microscopic staining techniques and high resolution (EM) cytochemistry, will be used for this purpose. Experiments will be carried out to define optimal conditions necessary for the successful maintenance and/or growth of type 1 cells in in vitro. Parameters to be considered will include the nature of substrates used for tissue culture, the number of isolates seeded and nutritional factors, such as media and sera. Once established, type 1 cell cultures will be utilized in basic metabolic studies of newly isolated type 1 cells, including DNA, protein, RNA and lipid synthesis. Also, measurements of cellular respiration will be made. Once baseline metabolic activities are defined, these data will by applied toward understanding type 1 cells under a variety of experimental conditions. An example of such studies will be undertaken in the final phase of this proposed research. Type 1 cells will be isolated from rabbits exposed to toxic levels of oxygen and basic metabolic measurements will serve to delineate changes occurring in type 1 cells due to oxygen poisoning.